In recent years, many engine manufacturers have developed and used turbine style fuel pumps to provide fuel to internal combustion engines. Turbine pumps have been preferred over more traditional fuel pumps employing gerotors or rolling vane components since turbine pumps generally are more efficient and less expensive to manufacture. However, since their inception turbine pumps have suffered from the limitation that, despite pushing fuel effectively out of the pump, they do not pull fuel into the pump very well. To overcome this weakness, turbine pumps are often placed within the fuel tanks from which they are drawing fuel, so as to reduce the force needed to pull fuel into the pumps. Placement of the pumps in the fuel tanks also reduces manufacturing costs since there is less concern over leakage from the pumps.
The use of in-tank turbine fuel pumps is an industry standard for automotive and power sports Electronic Fuel Injection (EFI) systems in particular. In-tank turbine fuel pumps are suitable for these industries because the engine manufacturers in these industries typically provide their own fuel tanks and fuel pumps that are specifically designed for use in conjunction with particular engines or vehicles. However, in-tank turbine fuel pumps are not particularly suitable in the area of small utility engines. Unlike manufacturers in the automotive and power sports industries, small utility engine manufacturers often try to utilize fuel systems that can be implemented universally on a wide variety of different types of engines and vehicles, and/or fuel systems that are applicable both to carbureted engines and to engines employing EFI systems. Indeed, it is typically desired that small utility engines be capable of universal (or largely universal) implementation in conjunction with a variety of vehicles and/or other applications. Yet the use of in-tank turbine fuel pumps in fuel tanks tends to limit the universality of application of those fuel systems with respect to different types of engines and vehicles.
Because of the restrictiveness of in-tank turbine fuel pumps in this regard, small utility engine manufacturers typically rely upon inline fuel pumps located outside of the fuel tanks instead of in-tank turbine fuel pumps. Yet although the use of in-line fuel pumps in conjunction with fuel tanks on small utility engines and associated vehicles enhances the universality of those fuel tanks/pumps with respect a variety of engines/vehicles, there are nevertheless certain other disadvantages associated with the use of in-line pumps in these applications. One disadvantage of using an in-line fuel pump is that it typically is only available with oversized flow capacity to produce the high-pressure necessary to pressurize an EFI system. This over-sizing typically results in a fuel flow that is three to eight times the flow capacity required. Also, the pressure of the fuel exiting the in-line fuel pump often may have a tendency to exceed the pressure required by the EFI system, and so there usually is a need to regulate the pressure of the fuel output by the fuel pump through the use of a pressure regulator.
The use of a pressure regulator in conjunction with the fuel tank and in-line fuel pump in turn complicates the design of the fuel delivery system. Not only must the fuel pressure regulator itself be mounted upon the engine/vehicle upon which the fuel delivery system is being implemented, but also a return fuel line must be provided to link the pressure regulator back to the fuel tank to allow for fuel exiting the regulator (as occurs when the pressure regulator determines that the output pressure of the fuel pump is excessive) to be returned to the fuel tank. Further, the implementation of the extra return fuel line necessitates the formation of an additional return hole in the OEM fuel tank wall. Modification of the fuel tank to in this manner can undermine any warranty provided by the OEM in relation to the fuel tank, and also can potentially decrease the useful life and reliability of the fuel tank.
The conventional arrangements of in-line fuel pumps in relation to small utility engines and associated vehicles are disadvantageous for additional reasons as well. For example, because such conventional arrangements tend to employ oversized in-line fuel pumps, operation of the pumps tends to consume relatively large amounts of power from the vehicle's electrical system. This is disadvantageous particularly in relation to small utility engines, which have limited battery recharging capabilities due to their size and power output. Further, conventional arrangements also are relatively incompatible with the process of upgrading a carbureted engine into an EFI engine. To upgrade an engine in this manner, the party performing the modification must perform multiple modifications to the engine so as to accommodate each of the electronic fuel pump, the pressure regulator and the return line back to the fuel tank.
For at least these reasons, therefore, it would be advantageous if an improved engine mounted fuel delivery system could be developed. More particularly, it would be advantageous if in at least some embodiments the improved engine mounted fuel delivery system could be more easily implemented in conjunction with a variety of types of engines and/or associated vehicles (or in conjunction with other applications), including engines/vehicles employing EFI systems. Additionally, it would be advantageous if in at least some embodiments the improved engine mounted fuel delivery system was particularly suitable for use in conjunction with small utility engines in that the fuel delivery system enhanced, or at least did not detract from, the universality of those engines with respect to different vehicle or other applications. Further, it would be advantageous if in at least some embodiments the improved engine mounted fuel delivery system could be easily implemented upon an engine that was previously a carbureted engine but was being modified to employ an EFI system. Additionally, in at least some embodiments, it would be advantageous if the demand imposed by such an improved engine mounted fuel delivery system upon an associated engine or vehicle's electrical system was reduced by comparison with conventional arrangements.